More from WebMD

May 31, 2011 -- Leading a stressful life isn't likely to raise the risk of developing multiple sclerosis (MS), according to a new study.

Researchers say exposure to stress has long been suspected to play a role in aggravating existing MS, but it has not been previously established whether stressful life events could increase the risk of developing MS.

"This rules out stress as a major risk factor for MS," researcher Trond Riise, PhD, of the University of Bergen, Norway, says in a news release.

"While we've known that stressful life events have been shown to increase the risk of MS episodes, we weren't certain whether these stressors could actually lead to developing the disease itself," says Riise, who conducted the research as a visiting scholar at the Harvard School of Public Health. "Future research can now focus on repeated and more fine-tuned measures of stress."

Multiple sclerosis is a chronic disease involving the immune system that affects the brain and spinal cord and causes periodic bouts of muscle pain and weakness. Although its exact cause is unknown, it is thought to include genetic and environmental components.

Stress at Home and Work

In the study, published in Neurology, researchers looked at the relationship between stress and the risk of developing multiple sclerosis in more than 237,000 women who participated in the Nurses Health Studies.

The participants reported the level of general stress at home and at work, including physical and sexual abuse in childhood and adolescence.

After taking into consideration other risk factors for multiple sclerosis, including age, ethnicity, latitude of birth, body mass at age 18, and smoking status, the researchers found severe stress at home or at work was not associated with any increase in MS risk.

In addition, there was no increase in multiple sclerosis risk among the women who reported severe physical or sexual abuse during childhood or adolescence.

The researchers say the results suggest that stress does not play a major role in the development of MS, but future studies are needed to fully exclude stress as a risk factor for multiple sclerosis.